Corrosion resistance of high nickel alloys in solar salt at 600 °C for up to 4000 h

Abstract

This study focuses on the time dependent performance of the corrosion resistance of IN625, H230 and 740H alloys in the solar salt (60 wt% NaNO 3 , 40 wt% KNO 3 , at 600 °C) for up to 4000 h. Alloy IN625 showed the lowest mass change with parabolic oxidation kinetics that tends to stabilize with exposure time. Both 740H and H230 alloys deviated from the parabolic oxidation behavior beyond the 3000 h of exposure. Alloy 740H showed the highest mass loss due to the nonuniform surface oxidation and the high chromium dissolution rate. Internal oxidation was noticed with Alloy H230 due to the high tungsten concentrations. • Oxidation of Alloy IN625 was found to follow a parabolic behavior that tends to stabilize with time. • Oxidation of 740H and H230 alloys deviated from the parabolic behavior after 3000 h of exposure. • Alloy 740H showed a nonuniform oxide layer and so has the highest mass loss. • Alloy H230 suffered of internal oxidation due to the high tungsten concentration.